Non-cooperative Laser Target Enhancement System And Method - Patent 8076624

Document Sample
Non-cooperative Laser Target Enhancement System And Method - Patent 8076624 Powered By Docstoc
Description: FIELD OF INVENTION The present invention relates to a method and several system implementations for projection of laser beams through a turbulent medium with a non-cooperative target using a combination of an adaptive optical system and an ultra-short temporalcoherence length laser source to form a controllable focused laser beacon at the target. A non-cooperative target refers to a target in which no laser beacon is provided directly by the target for wavefront sensing. The present invention provides asystem and method to form a near diffraction limited size beacon for an adaptive optical system using a temporally partially coherent laser source.BACKGROUND OF THE INVENTION Adaptive optical system technology has proven itself invaluable to a number of applications such as astronomical imaging and long range optical communication through the atmosphere. Adaptive optical system technology can potentially enhance anyapplication in which turbulence along the path, which leads to refractive index fluctuations due to temperature variations, degrades the performance of an imaging or laser projection system. Methods are well known in the prior art for dealing with greatdistances and associated phenomena of strong scintillation (wherein branch points in the phase function begin to dominate performance and amplitude fluctuations can begin to degrade performance). These methods have an important limitation that hasremained unsolved throughout the history of the field: the only highly successful applications of adaptive optical systems to date are when a "cooperative" point source laser beacon at the target is provided. The point source beacon projected from thetarget is used to make wavefront sensing measurements of the distortions along the path for pre-compensation of a laser beam by the adaptive optical system. Many potential applications of adaptive optical systems, including laser radar, laserrangefinding, directed energy, and ophthalmic imaging all have "non-coope